What is the difference between a linked list and an array?

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What is the difference between a linked list and an array?

A linked list and an array are both data structures used to store and organize data, but they have several key differences.

1. Memory Allocation: In an array, memory is allocated in a contiguous block, meaning that all elements are stored in adjacent memory locations. On the other hand, a linked list uses dynamic memory allocation, where each element (node) is stored in a separate memory location and connected through pointers.

2. Size: Arrays have a fixed size, determined at the time of declaration, and cannot be easily resized. In contrast, linked lists can dynamically grow or shrink in size as elements are added or removed.

3. Insertion and Deletion: Inserting or deleting an element in an array requires shifting all subsequent elements to accommodate the change, which can be time-consuming for large arrays. In a linked list, insertion or deletion can be done efficiently by simply updating the pointers of the adjacent nodes.

4. Access Time: Arrays provide constant-time access to elements based on their index, as they can be directly accessed using the index value. Linked lists, however, require traversing the list from the beginning to reach a specific element, resulting in a linear search time.

5. Memory Efficiency: Arrays are generally more memory-efficient than linked lists because they do not require additional memory for storing pointers. Linked lists, on the other hand, require extra memory for storing the pointers that connect the nodes.

6. Flexibility: Arrays are suitable for situations where random access to elements is required, such as searching or sorting algorithms. Linked lists are more flexible when it comes to dynamic data structures, as they can easily accommodate changes in size and structure.

7. Implementation: Arrays are a built-in data structure in most programming languages, making them easier to use and implement. Linked lists, although not as commonly used, require manual implementation using pointers or references.

In summary, the main differences between a linked list and an array lie in their memory allocation, size flexibility, efficiency in insertion/deletion, access time, memory usage, and implementation complexity. The choice between the two depends on the specific requirements of the problem at hand.